System and method for radio frequency penetration imaging of an object

ABSTRACT

A system and methods for RF (Radio Frequency) penetration imaging of one or more objects in a medium, the system including a generation and reception subsystem configured to generate and receive a plurality of RF signals, an RF antenna array including a plurality of antennas, the antennas being configured to transmit the RF signals towards the medium and receive a plurality of RF signals reflected from the medium, a data acquisition subsystem configured to receive and store the reflected RF signals, and a processor configured to estimate the distance between the surface of the target medium and the antenna array, the delay between the transmitted signals and the plurality of signals reflected from the object using a dedicated frequency sub-band of the received signals, the location of the antennas at each transmitting time, and determine whether there is an object within the medium.

FIELD OF THE INVENTION

The present invention relates to a system and method for imaging anobject or structure and more specifically, but not exclusively, to RF(Radio Frequency) penetration imaging of an object or structure within amedium.

BACKGROUND OF THE INVENTION

Prior RF devices for imaging or scanning within a medium, such as groundpenetrating radars (GPR), typically assume a fixed, or minimalvariation, distance between the imaging device antennas to the surfaceof the medium throughout the scanning or imaging process. Moreover, thisdistance is typically smaller than the transmission wavelength (i.e.sub-wavelength distance), i.e. the imaging device antennas are attachedor in very close proximity to the surface of the medium.

These two assumptions, separately, and together, play an important rolein the ability to form a coherent and accurate image for the analysis ofthe underlying structures and objects within the medium. Amongst suchimage techniques one finds, radiograms, migration techniques.

Knowing where the signals were collected relative to the medium surfaceis critical for an aligned focusing of the signals as part of theimaging and/or medium scanning process.

Additionally, the prior devices can be less than ideal in at least somerespects. Prior devices having high imaging and accurate capabilitiescan be larger than ideal for use in many portable applications. Also,the cost of prior devices can be greater than would be ideal. The priordevices can be somewhat bulky, difficult to activate requiring forexample specific and constant distance from the medium, for exampleprior devices must be attached to the medium.

In light of the above, an improved imaging system that overcomes atleast some of the above mentioned deficiencies of the prior deviceswould be beneficial. Ideally such imaging device would be a compact,integrated with a consumer device such as a cellular telephone,sufficiently rugged and low in cost to be practical for end-user imagingof objects or structures within a medium and convenient to use.

SUMMARY OF INVENTION

Prior to the Summary of the invention being set forth, it may be helpfulto set forth definitions of certain terms that will be used hereinafter.

The term ‘Penetration RF imaging’ or ‘Standoff penetration RF imaging’as used herein is defined as the process of imaging by an imaging systema medium internal structure or objects while not being in direct contactwith its surface, e.g. at a distance larger than the wavelength used bythe imaging device.

The term ‘target medium’ as used herein is defined as an homogeneous orclose to homogenous material in which scattering objects (i.e. objectsor structures of different electromagnetic properties than the medium)may be present in and may be for example air, concrete, plaster, fluids,human tissues etc.

The term ‘interim medium’ as used herein is defined as an homogeneous orclose to homogeneous material medium located between the device and thetarget medium, of different electromagnetic properties that the targetmedium, such that the surface of the target medium is distinct from theinterim medium, typically the interim medium being free of objects orstructures, the device moving freely in this medium, the interim mediummay be for example air, fluids, etc.

According to a first aspect of the invention there is provided a RF(Radio Frequency) imaging system, for imaging at least one object withina target medium, the system comprising a generation and reception unitconfigured to generate and receive a plurality of RF signals; an RFantenna array, the RF antenna array comprises a plurality of antennas,said plurality of antennas are configured to transmit the plurality ofRF signals towards the target medium and receive a plurality of RFsignals reflected from the target medium; a data acquisition unitconfigured to receive and store said plurality of reflected RF signals;and at least one processor unit, said at least one processor unit isconfigured to:estimate the distance between the surface of the targetmedium and the antenna array; calculate the delay between the pluralityof transmitted signals and the plurality of signals reflected from theat least one object; estimate the location of the plurality of antennasat each transmitting time; and provide an image of the at least oneobject location and the intensity of the plurality of reflected RFsignals.

In an embodiment, the at least one processor is configured to analyzethe angular orientation between the antenna array and the target mediumsurface.

In an embodiment, the system comprises a display and wherein the imageis displayed on said display.

In an embodiment, an interim medium is located between the target mediumand the antenna array of the imaging system and the antenna array ispositioned or moved in a distance from the target medium.

In an embodiment, the distance is constant or variable.

In an embodiment, the distance is larger than a wavelength.

In an embodiment, the interim medium or the target medium are selectedfrom the group consisting of: air, concrete, plaster, fluids, humantissues.

In an embodiment, the image is 2D (two dimension) or 3D (threedimension) image.

In an embodiment, the RF signals are Ultra Wide Band signals.

In an embodiment, the RF imaging system is portable.

In an embodiment, the antenna array is configured to communicate withorientation or measurements devices, said devices are selected from thegroup consisting of: accelerometers, gyros, laser distance measurementdevices.

According to a second aspect there is provided a method for imaging atleast one object within a target medium, the method comprising:transmitting a plurality of RF (radio frequency) signals by an RFantenna array, said RF antenna array comprises a plurality of RFantennas; receiving at said RF antenna array a plurality of RF signalsreflected from the at least one object; estimating the distance betweenthe surface of the target medium and the antenna array; calculating thedelay between the plurality of transmitted signals and the receivedsignals reflected from the at least one object;

In an embodiment, the method comprise estimating a location of theplurality of RF antennas at each transmitting time of said plurality oftransmitted signals; and providing an image the at least one objectlocation.

In an embodiment, the method comprising providing the intensity of thereflected RF signals from the at least one object.

In an embodiment, the meth comprising estimating the presence or lack ofthe at least one object.

In an embodiment, an interim medium is located between the target mediumand the antenna array of the imaging system and the antenna array ispositioned or moved in a distance from the target medium.

In an embodiment, the distance is constant or variable.

In an embodiment, the angular orientation between the antenna array andthe target medium surface is estimated from the received signals.

In an embodiment, the distance between the surface of the target mediumand the antenna array is estimated using the high frequency band of theplurality of received signals.

In an embodiment, the delay is estimated from a subset of the pluralityof received RF signals and/or using a dedicated frequency sub-band ofthe received signals.

In an embodiment, the estimation of the location or orientation of theantenna array is improved using measurements from at least one or moreaccelerometers, gyros, cameras, laser devices.

Unless otherwise defined, all technical and/or scientific terms usedherein have the same meaning as commonly understood by one of ordinaryskill in the art to which the invention pertains. Although methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of embodiments of the invention, exemplarymethods and/or materials are described below. In case of conflict, thepatent specification, including definitions, will control. In addition,the materials, methods, and examples are illustrative only and are notintended to be necessarily limiting.

Implementation of the method and/or system of embodiments of theinvention can involve performing or completing selected tasks manually,automatically, or a combination thereof. Moreover, according to actualinstrumentation and equipment of embodiments of the method and/or systemof the invention, several selected tasks could be implemented byhardware, by software or by firmware or by a combination thereof usingan operating system.

For example, hardware for performing selected tasks, according toembodiments of the invention, could be implemented as a chip or acircuit. As software, selected tasks according to embodiments of theinvention could be implemented as a plurality of software instructionsbeing executed by a computer using any suitable operating system. In anexemplary embodiment of the invention, one or more tasks according toexemplary embodiments of method and/or system as described herein, areperformed by a data processor, such as a computing platform forexecuting a plurality of instructions. Optionally, the data processorincludes a volatile memory for storing instructions and/or data and/or anon-volatile storage, for example, a magnetic hard-disk and/or removablemedia, for storing instructions and/or data. Optionally, a networkconnection is provided as well. A display and/or a user input devicesuch as a keyboard or mouse are optionally provided as well.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter disclosed may best be understood by reference to thefollowing detailed description when read with the accompanying drawingsin which:

FIG. 1 is a simplified schematic diagram illustrating a user scanningthe surface of a target medium by a mobile device, in accordance withexamples;

FIG. 2 is a schematic view of an RF penetration imaging system, inaccordance with examples;

FIG. 3 is a simplified block diagram showing a system configuration forimaging a medium in accordance with examples;

FIG. 4 is a flowchart illustrating a method for imaging a target mediumand one or more objects located within a medium, in accordance withexamples; and

FIG. 5 is a simplified block diagram illustrating a rotation angle ofthe imaging in accordance with examples.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a system, device and methods for RFimaging an object or structure within a medium and more specifically,but not exclusively, to an RF penetration imaging within a medium forexample a standoff RF penetration imaging.

Embodiments of the disclosure provide a system and methods for imaging(e.g. 2D imaging or 3D imaging) of one or more objects (e.g. hiddenobjects to be imaged such as pipe or a miniaturized element) inside atarget medium (e.g. solid medium such as a wall). The system comprisesan RF unit configured to transmit and receive RF signals which penetratethrough the target medium (e.g. wall, fluids, etc.), one or moreprocessing units configured to process the multiple RF signals reflectedfrom the objects and/or the target medium surface and to provide animage of the hidden objects. The visualization may be or may include agraphical visualization (e.g. rendered graphical visualization). Forexample, the graphical visualization may include an image such as a 2Dor 3D image of the hidden objects inside the target medium comprisingone or more of the object's parameters such as size, width volume etc.,or indication of the presence or lack of objects within the medium. Insome cases, an interim medium is located between the target medium andthe imaging device and the antenna array may be positioned or moved at adistance from the medium.

Specifically, a system and methods disclosed herein comprise scanning orimaging a medium regardless of the distance between the device (e.g. thedevice antennas) and the target medium surface, e.g. allowing for thedistance from device antennas (e.g. the antenna array) to the targetmedium surface to change throughout the scanning process and not belimited to near field (e.g. sub-wavelength and/or comparable wavelength)distance, for example, attached or almost attached to the target mediumor far-field (e.g. larger than wavelength) standoff distance.

In other words, the two prior art assumptions mentioned herein above,i.e. requiring constant distance between the imaging device antennas tothe surface of the target medium throughout the scanning or imagingprocess and/or a distance smaller than the antenna wavelength, areeliminated according to the present invention embodiments.

In some cases, received RF signals, for example signals received by thesystem's receive antennas are combined in a coherent way by compensatingfor the occurred propagation delays within the medium. These delays canbe estimated from a subset of received RF signals and/or for exampleusing a dedicated frequency sub-band of the received signals.

According to some embodiments the system and method may be used inconjunction with additional orientation and/or distance measurementdevices including for example accelerometers, gyros, laser distancemeasuring devices.

Before explaining at least one embodiment of the invention in detail, itis to be understood that the invention is not necessarily limited in itsapplication to the details of construction and the arrangement of thecomponents and/or methods set forth in the following description and/orillustrated in the drawings and/or the examples. The invention iscapable of other embodiments or of being practiced or carried out invarious ways.

Referring now to the drawings, FIG. 1 is a simplified schematic diagramshowing a user 120 scanning the surface of a target medium such as awall 140 by an imaging device 130. In some embodiments the imagingdevice 130 may be in communication or mounted possibly but notexclusively as an add-on, for example on a mobile device 100, (e.g.mobile phone). The target medium may be made of for example a solidelement such as wood, stone, gypsum, concrete or non solid elements suchas air, water, or a combination thereof. The mobile device 100 may befor example a communication mobile device such as a mobile phone forexample a smartphone or a tablet as will be illustrated specificallyherein below in FIG. 2.

In operation, the user 120 places the imaging device 130 in proximity tothe wall for example in parallel to the wall (e.g. in front of the wall,few cm from the surface of the wall for example between 1-100 cm fromthe wall, or less). The distance may change during the scanning. Oncethe user 120 scans the wall, one or more hidden objects such as verticalrebars 122 and 123 embedded within the wall in front or in proximity tothe device 130 may be imaged and displayed to the user in real time (oroffline), for example on a display unit 110 of the device 100. In somecases the image may include a 3D image of the objects including specificinformation of the object's parameters such as size, orientation,radius, depth, and distance from the object to the imaging device. Insome cases a complete image of the wall 140 and the internal objectsembedded in the wall 140 may be identified and imaged.

In some cases, the image may be or may include a visualization such as agraphical visualization or a rendered graphical visualization of theobject including the object's parameters such as size, orientation,distance from the medium etc.

According to some embodiments the imaging device 130 is furtherconfigured to interface with the mobile device 100 computing platform.The mobile device 100 may be for example a smartphone which may includea processor and software modules associated with the imaging device 130which are executed by the mobile device processor.

For example, the imaging device 130 may be attached to the mobile device100, and the imaging device 130 may be in communication to one or moreprocessing units and/or a display unit of the mobile device 100.

In some case, the user 120 may scan the surface of the wall by theimaging device 130 and the scanned data may be transmitted via wire orwireless connection to a database unit located for example in a cloud orin the mobile device 100 and the scanned data may be processed by one ormore external processing units or internal processing unit of theimaging device 130 or the mobile device 100.

According to some embodiments, the imaging device 130 may be astandalone device, for example a standalone portable device.

In some cases the scanned date (e.g. graphic visualization, parameters,or an image of the object) may be displayed to the user on headset(goggles) such as a VR (Virtual Reality) and/or AR (Augmented Reality)headset or on the mobile device such as smartphone.

The imaging device 130 and/or the mobile device 100 can have a size andweight such that the device can be held by a user with only one hand.The imaging device 130 can have a size and weight such that the devicecan be portable. The device can have a weight of about 100 gram (g), 200g, 300 g, 400 g, 500 g, 600 g, 700 g, 800 g, 900 g, 1000 g. The imagingdevice can have a weight that is between any of the two values givenabove. The imaging device can have a weight greater than 1000 g.

The imaging device 130 shape can comprise a rectangular prism, cylinder,or other three-dimensional shape.

One or more of the components of the imaging device 130 can be poweredby a battery.

FIG. 2 is block diagram illustrating the architecture of an RFpenetration imaging system 200. The system comprises the principalfunctions of the above mentioned imaging device 130 and relevantfunctions of a mobile device 100 which may be attached to or incommunication with it.

The imaging system 200 may include an RF signal generation and receptionsubsystem 204, an antenna array subsystem 202, a data acquisitionsubsystem 206, and one or more data processors or processing units 208,and additional sensors such as one or more accelerometers and/orgyroscopes 211 and/or one or more cameras 213 and/or a console 210 (fordisplay storage and analysis).

The RF signal generation and reception (transmit-receive) subsystem 204is responsible for generation of the microwave signals, coupling them tothe antennas 202 a-202 e, reception of the microwave signals from theantennas and converting them into a form suitable for acquisition. TheRF signals can be pulse signals, stepped-frequency signals, chirpsignals and the like. The generation circuitry can involve oscillators,synthesizers, mixers, or it can be based on pulse oriented circuits suchas logic gates or step-recovery diodes. For example these signals may bemicrowave signals in the UWB band 3, 4, 5, 6, 7, 8, 9 or 10 GHz (havinga wavelength of 10-3 cm correspondingly in air).

The conversion process can include down conversion, sampling, and thelike. The conversion process typically includes averaging in the form oflow-pass filtering, to improve the signal-to-noise ratios and to allowfor lower sampling rates. The RF signal generation and receptionsubsystem 204 can perform transmission and reception with multipleantennas at a time or select one transmit and one receive antenna at atime, according to a tradeoff between complexity and acquisition time.In an embodiment, the RF signal generation and reception subsystem 204may comprise a single RF Integrated Circuit (RFIC) or several RFICs.

The imaging system 200 may include one or more antennas such as antennaarray 202. For example the antenna array 202 may include multipleantennas 202 a-202 e typically between a few and several dozen (forexample 30) antennas. The antennas can be of many types known in theart, such as printed antennas, waveguide antennas, dipole antennas or“Vivaldi” broadband antennas. The antenna array can be linear ortwo-dimensional, flat or conformal to the region of interest.

According to one embodiment, the antenna array 202 comprises a number ofantennas for each frequency range, or a single antenna for eachfrequency range, or a single antenna supporting the entire frequencyrange. According to another example, the array may include 20 antennaswhere 5 antennas are dedicated for each out of the 4 frequency bands.

According to some embodiment, the antenna array 202 may be an array offlat broadband antennas, for example spiral shaped antennas. The antennaarray 202 may include a layer of matching material for improved couplingof the antenna radiation to the materials or objects under test. Theunique and optimized shape of the antenna array enables their use inlimited sized mobile devices, such as a thin, small-sized smart phone ortablet.

The data acquisition subsystem 206 collects and digitizes the signalsfrom the RF signal generation and reception subsystem 204 while taggingthe signals according to the antenna combination used and the time atwhich the signals were collected. The data acquisition subsystem willtypically include analog-to-digital (A/D) converters and data buffers,but it may include additional functions such as signal averaging,correlation of waveforms with templates or converting signals betweenfrequency and time domain.

The data acquisition subsystem 206 may include a Radio Frequency SignalsImaging device (RFSMU) such as a Vector Network Analyzer (VNA) formeasuring the received/reflected signals.

The data processing unit 208 is responsible for converting the collectedsignals into a set of responses characterizing the target objects, andperforming the algorithms for converting the sets of responses, forexample providing the location of the target objects, the intensity ofthe signal reflection from the objects.

Example of algorithms for converting the sets of responses may be forexample Delay and Sum (DAS) algorithm, PFA (polar format SAR algorithm),RMA (Range Migration Algorithm).

According to some embodiments, the imaging system 200 may includeaccelerometers and/or gyros and/or laser distance measuring devices 211to fine tune and give additional data in respect to the movement or thedistance of the imaging system 200.

Additionally, the imaging system 200 may include a camera 213 to obtainthe system relative location or movement in respect to a referencelocation, as will be illustrated in details hereinabove.

Such additional measurements can be used as prior information to improvethe location and orientation calculation using the signals received andtransmitted by the antennas, or can be used to improve the calculationof location and orientation after it has been calculated from thesignals received and transmitted by the antennas. The improvement can beachieved using a variety of methods, such as Kalman Filtering, ParticleFiltering, Bayesian Filtering or other methods. Once the location andorientation information of the antennas array were calculated, it can beused in the imaging process as displacement information betweenmeasurements, for example in migration algorithms.

A final step in the process includes making use of the resultingparameters or image, either in the form of visualization, display,storage, archiving, or input to feature detection algorithms. This stepis exemplified in FIG. 2 as console 210. The console for example may bepart of a mobile device for example implemented as a handheld computersuch as a mobile phone, laptop computer or a desktop computer withappropriate application software.

According to one embodiment of this invention, an imaging device 230,which is part of the RF penetration imaging system 200, may comprise theRF transmit-receive subsystem 204 and the antenna array subsystem 202 asshown in FIG. 2, while a mobile device 220 (e.g. mobile phone) maycomprise some or all the remaining functional blocks of 200. The imagingdevice may be connected to the mobile device 220, for example through adedicated connection such a USB connection, wireless connection or anyconnection known in the art. Following the connection of the imagingdevice 230 to the mobile device 220, the imaging device 230 may utilizethe mobile device's own data acquisition, data processing display, andstorage and analysis subsystems.

According to another embodiment, data acquisition subsystem 206, dataprocessing unit 208 as well as measuring devices 211 and 213 may also bepart of the imaging device 230 (in addition to RF transmit-receivesubsystem 204 and the antenna array subsystem 202). The console 210 mayalso be integrated into the imaging device 230, thus getting a completestand alone system. Alternatively, the console 210 is typicallyimplemented as a handheld computer such as a mobile phone or a desktopcomputer with appropriate application software. It is stressed thatother embodiments comprising alternative arrangements of the subsystemsbetween the imaging device 230 the RF penetration imaging system 200 andthe mobile device are applicable.

FIG. 3 is a simplified block diagram side view description showing asystem configuration 300 for imaging a target medium 340 and one or moreobjects (e.g. one or more scattering objects 350) within the targetmedium in accordance with embodiments.

The system 300 comprises an RF penetration imaging system 320 which maycomprise one of the units and subsystems illustrated in system 200 ofFIG. 2. Only the antenna array subsystem 302, the RF generation andreception subsystem 304 and the data acquisition subsystem 306 andprocessing unit 308 are shown in FIG. 3.

In operation, the imaging device is positioned and/or moved at adistance 370 from the target medium surface 333. The distance 370 maythe distance between the antenna array 302 and the target medium outersurface 333. In some cases the distance 370 may be constant or variableas the user scans and image the target medium. During the scanningprocess the antenna array 302 transmits one or more RF signals generatedby the RF signal generation and reception subsystem 304 towards thetarget medium 340. When the antenna array 302 is not attached to thetarget medium 340 (or in very close proximity with it), e.g. at astandoff distance, the RF signals propagate through an interim medium330. In some instances, the interim medium 330 may be or may include airor other intermediate matched medium located between the antenna array302 and a target medium 340.

FIG. 4 is a flowchart 400 illustrating a method for imaging one or moreobjects located within the target medium, in accordance withembodiments.

Step 410 comprises transmitting one or more RF signals by one or moreantennas of the antenna array 302 and step 415 comprises receiving atthe antenna array one or more signals reflected by the outer surface 333of the target medium and/or by the objects 350 within the target medium.

Step 420 comprises estimating the distance 370 between the antenna arrayand the outer surface 333 of the target medium, for example estimatingthe distance between the surface of the target medium 340 and theantenna array 302. This distance estimation may be provided, forexample, using the high frequency band of the RF signals. For example(for a case where the entire band is 3-10 GHz) the higher frequency bandof the signals used for this estimation may be 6-10 GHz. In addition,step 420 includes evaluation of the antenna array angular orientation inrespect to the target medium surface. For example as illustrated in FIG.5, the angular orientation may include the rotation angle α of theantenna array 502 in respect to the surface of the target medium 540.

Step 430 comprises measuring the propagation delay between thetransmitted signals and received signals reflected by the scatteringobjects 350 inside the target medium 340. The different electromagneticproperties of the interim and target medium materials and the distancemeasured in accordance with step 420 are taken into account to separatethe delay incurred within the target medium (i.e. the propagation delayfrom the outer surface of the target medium to the object) out of theoverall propagation delay.

Step 440 comprises estimating the location of each antenna in space(e.g. antenna 302 a-d) relative to the target medium (e.g. the surface333 of the target medium 340) during the scanning process (e.g. whiletransmitting and receiving the signals affected by the medium). Thisestimation can be performed using, but not limited to, inertialmeasurements device on the antennas or the signals themselves.

Step 450 comprises providing an image of the scattered objects 350location and the intensity of their reflected RF signal, using one ormore methods, such as, but not limited to, DAS (delay and sum), PFA(polar format SAR algorithm), RMA (Range Migration Algorithm).

Step 460 comprises estimating the presence or lack of scattered objectsinside the target medium according to the image provided in step 450.

This embodiment can use RF signals such as UWB (Ultra Wide Band)signals, covering a large frequency range (e.g. 3-10 GHz). The higherfrequency band of the signals (e.g. 6-10 GHz) enable increased accuracyin estimating the distance between the antenna array and the surface 333of the target medium (Step 420). It is noted that typically thepropagation path loss in the interim medium is small in spite of thehigh frequencies used. The whole frequency band of the RF signals andthe lower frequency band in particular, are used to estimate the overalldelay (Step 430), with a larger (but sufficient) accuracy. It is notedthat at lower frequencies the signals incur a smaller propagation pathloss in the target medium.

In further embodiments, the processing unit may be a digital processingdevice including one or more hardware central processing units (CPU)that carry out the device's functions. In still further embodiments, thedigital processing device further comprises an operating systemconfigured to perform executable instructions. In some embodiments, thedigital processing device is optionally connected a computer network. Infurther embodiments, the digital processing device is optionallyconnected to the Internet such that it accesses the World Wide Web. Instill further embodiments, the digital processing device is optionallyconnected to a cloud computing infrastructure. In other embodiments, thedigital processing device is optionally connected to an intranet. Inother embodiments, the digital processing device is optionally connectedto a data storage device.

In accordance with the description herein, suitable digital processingdevices include, by way of non-limiting examples, server computers,desktop computers, laptop computers, notebook computers, sub-notebookcomputers, netbook computers, netpad computers, set-top computers,handheld computers, Internet appliances, mobile smartphones, tabletcomputers, personal digital assistants, video game consoles, andvehicles. Those of skill in the art will recognize that many smartphonesare suitable for use in the system described herein. Those of skill inthe art will also recognize that select televisions with optionalcomputer network connectivity are suitable for use in the systemdescribed herein. Suitable tablet computers include those with booklet,slate, and convertible configurations, known to those of skill in theart.

In some embodiments, the digital processing device includes an operatingsystem configured to perform executable instructions. The operatingsystem is, for example, software, including programs and data, whichmanages the device's hardware and provides services for execution ofapplications. Those of skill in the art will recognize that suitableserver operating systems include, by way of non-limiting examples,FreeBSD, OpenBSD, NetBSD®, Linux, Apple® Mac OS X Server®, Oracle®Solaris®, Windows Server®, and Novell® NetWare®. Those of skill in theart will recognize that suitable personal computer operating systemsinclude, by way of non-limiting examples, Microsoft® Windows®, Apple®Mac OS X®, UNIX®, and UNIX-like operating systems such as GNU/Linux®. Insome embodiments, the operating system is provided by cloud computing.Those of skill in the art will also recognize that suitable mobile smartphone operating systems include, by way of non-limiting examples, Nokia®Symbian® OS, Apple® iOS®, Research In Motion® BlackBerry OS®, Google®Android®, Microsoft® Windows Phone® OS, Microsoft® Windows Mobile® OS,Linux®, and Palm® WebOS®.

In some embodiments, the device includes a storage and/or memory device.The storage and/or memory device is one or more physical apparatusesused to store data or programs on a temporary or permanent basis. Insome embodiments, the device is volatile memory and requires power tomaintain stored information. In some embodiments, the device isnon-volatile memory and retains stored information when the digitalprocessing device is not powered. In further embodiments, thenon-volatile memory comprises flash memory. In some embodiments, thenon-volatile memory comprises dynamic random-access memory (DRAM). Insome embodiments, the non-volatile memory comprises ferroelectric randomaccess memory (FRAM). In some embodiments, the non-volatile memorycomprises phase-change random access memory (PRAM). In otherembodiments, the device is a storage device including, by way ofnon-limiting examples, CD-ROMs, DVDs, flash memory devices, magneticdisk drives, magnetic tapes drives, optical disk drives, and cloudcomputing based storage. In further embodiments, the storage and/ormemory device is a combination of devices such as those disclosedherein.

In some embodiments, the digital processing device includes a display tosend visual information to a user. In some embodiments, the display is acathode ray tube (CRT). In some embodiments, the display is a liquidcrystal display (LCD). In further embodiments, the display is a thinfilm transistor liquid crystal display (TFT-LCD). In some embodiments,the display is an organic light emitting diode (OLED) display. Invarious further embodiments, on OLED display is a passive-matrix OLED(PMOLED) or active-matrix OLED (AMOLED) display. In some embodiments,the display is a plasma display. In other embodiments, the display is avideo projector. In still further embodiments, the display is acombination of devices such as those disclosed herein.

In some embodiments, the digital processing device includes an inputdevice to receive information from a user. In some embodiments, theinput device is a keyboard. In some embodiments, the input device is apointing device including, by way of non-limiting examples, a mouse,trackball, track pad, joystick, game controller, or stylus. In someembodiments, the input device is a touch screen or a multi-touch screen.In other embodiments, the input device is a microphone to capture voiceor other sound input. In other embodiments, the input device is a videocamera to capture motion or visual input. In still further embodiments,the input device is a combination of devices such as those disclosedherein.

In some embodiments, the system disclosed herein includes one or morenon-transitory computer readable storage media encoded with a programincluding instructions executable by the operating system of anoptionally networked digital processing device. In further embodiments,a computer readable storage medium is a tangible component of a digitalprocessing device. In still further embodiments, a computer readablestorage medium is optionally removable from a digital processing device.

In some embodiments, a computer readable storage medium includes, by wayof non-limiting examples, CD-ROMs, DVDs, flash memory devices, solidstate memory, magnetic disk drives, magnetic tape drives, optical diskdrives, cloud computing systems and services, and the like. In somecases, the program and instructions are permanently, substantiallypermanently, semi-permanently, or non-transitorily encoded on the media.In some embodiments, the system disclosed herein includes at least onecomputer program, or use of the same. A computer program includes asequence of instructions, executable in the digital processing device'sCPU, written to perform a specified task. Computer readable instructionsmay be implemented as program modules, such as functions, objects,Application Programming Interfaces (APIs), data structures, and thelike, that perform particular tasks or implement particular abstractdata types. In light of the disclosure provided herein, those of skillin the art will recognize that a computer program may be written invarious versions of various languages.

The functionality of the computer readable instructions may be combinedor distributed as desired in various environments. In some embodiments,a computer program comprises one sequence of instructions. In someembodiments, a computer program comprises a plurality of sequences ofinstructions. In some embodiments, a computer program is provided fromone location. In other embodiments, a computer program is provided froma plurality of locations. In various embodiments, a computer programincludes one or more software modules. In various embodiments, acomputer program includes, in part or in whole, one or more webapplications, one or more mobile applications, one or more standaloneapplications, one or more web browser plug-ins, extensions, add-ins, oradd-ons, or combinations thereof.

In some embodiments, a computer program includes a mobile applicationprovided to a mobile digital processing device. In some embodiments, themobile application is provided to a mobile digital processing device atthe time it is manufactured. In other embodiments, the mobileapplication is provided to a mobile digital processing device via thecomputer network described herein.

In view of the disclosure provided herein, a mobile application iscreated by techniques known to those of skill in the art using hardware,languages, and development environments known to the art. Those of skillin the art will recognize that mobile applications are written inseveral languages. Suitable programming languages include, by way ofnon-limiting examples, C, C++, C#, Objective-C, Java™, Javascript,Pascal, Object Pascal, Python™, Ruby, VB.NET, WML, and XHTML/HTML withor without CSS, or combinations thereof.

Suitable mobile application development environments are available fromseveral sources. Commercially available development environmentsinclude, by way of non-limiting examples, AirplaySDK, alcheMo,Appcelerator®, Celsius, Bedrock, Flash Lite, .NET Compact Framework,Rhomobile, and WorkLight Mobile Platform. Other development environmentsare available without cost including, by way of non-limiting examples,Lazarus, MobiFlex, MoSync, and Phonegap. Also, mobile devicemanufacturers distribute software developer kits including, by way ofnon-limiting examples, iPhone and iPad (iOS) SDK, Android™ SDK,BlackBerry® SDK, BREW SDK, Palm® OS SDK, Symbian SDK, webOS SDK, andWindows® Mobile SDK.

Those of skill in the art will recognize that several commercial forumsare available for distribution of mobile applications including, by wayof non-limiting examples, Apple® App Store, Android™ Market, BlackBerry®App World, App Store for Palm devices, App Catalog for webOS, Windows®Marketplace for Mobile, Ovi Store for Nokia® devices, Samsung® Apps, andNintendo® DSi Shop.

In some embodiments, the system disclosed herein includes software,server, and/or database modules, or use of the same. In view of thedisclosure provided herein, software modules are created by techniquesknown to those of skill in the art using machines, software, andlanguages known to the art. The software modules disclosed herein areimplemented in a multitude of ways. In various embodiments, a softwaremodule comprises a file, a section of code, a programming object, aprogramming structure, or combinations thereof. In further variousembodiments, a software module comprises a plurality of files, aplurality of sections of code, a plurality of programming objects, aplurality of programming structures, or combinations thereof. In variousembodiments, the one or more software modules comprise, by way ofnon-limiting examples, a web application, a mobile application, and astandalone application. In some embodiments, software modules are in onecomputer program or application. In other embodiments, software modulesare in more than one computer program or application. In someembodiments, software modules are hosted on one machine. In otherembodiments, software modules are hosted on more than one machine. Infurther embodiments, software modules are hosted on cloud computingplatforms. In some embodiments, software modules are hosted on one ormore machines in one location. In other embodiments, software modulesare hosted on one or more machines in more than one location.

In some embodiments, the system disclosed herein includes one or moredatabases, or use of the same. In view of the disclosure providedherein, those of skill in the art will recognize that many databases aresuitable for storage and retrieval of information as described herein.In various embodiments, suitable databases include, by way ofnon-limiting examples, relational databases, non-relational databases,object oriented databases, object databases, entity-relationship modeldatabases, associative databases, and XML, databases. In someembodiments, a database is internet-based. In further embodiments, adatabase is web-based. In still further embodiments, a database is cloudcomputing-based. In other embodiments, a database is based on one ormore local computer storage devices.

In the above description, an embodiment is an example or implementationof the inventions. The various appearances of “one embodiment,” “anembodiment” or “some embodiments” do not necessarily all refer to thesame embodiments.

Although various features of the invention may be described in thecontext of a single embodiment, the features may also be providedseparately or in any suitable combination. Conversely, although theinvention may be described herein in the context of separate embodimentsfor clarity, the invention may also be implemented in a singleembodiment.

Reference in the specification to “some embodiments”, “an embodiment”,“one embodiment” or “other embodiments” means that a particular feature,structure, or characteristic described in connection with theembodiments is included in at least some embodiments, but notnecessarily all embodiments, of the inventions.

It is to be understood that the phraseology and terminology employedherein is not to be construed as limiting and are for descriptivepurpose only.

The principles and uses of the teachings of the present invention may bebetter understood with reference to the accompanying description,figures and examples.

It is to be understood that the details set forth herein do not construea limitation to an application of the invention.

Furthermore, it is to be understood that the invention can be carriedout or practiced in various ways and that the invention can beimplemented in embodiments other than the ones outlined in thedescription above.

It is to be understood that the terms “including”, “comprising”,“consisting” and grammatical variants thereof do not preclude theaddition of one or more components, features, steps, or integers orgroups thereof and that the terms are to be construed as specifyingcomponents, features, steps or integers.

If the specification or claims refer to “an additional” element, thatdoes not preclude there being more than one of the additional element.

It is to be understood that where the claims or specification refer to“a” or “an” element, such reference is not be construed that there isonly one of that element.

It is to be understood that where the specification states that acomponent, feature, structure, or characteristic “may”, “might”, “can”or “could” be included, that particular component, feature, structure,or characteristic is not required to be included.

Where applicable, although state diagrams, flow diagrams or both may beused to describe embodiments, the invention is not limited to thosediagrams or to the corresponding descriptions. For example, flow neednot move through each illustrated box or state, or in exactly the sameorder as illustrated and described.

Methods of the present invention may be implemented by performing orcompleting manually, automatically, or a combination thereof, selectedsteps or tasks.

The descriptions, examples, methods and materials presented in theclaims and the specification are not to be construed as limiting butrather as illustrative only.

Meanings of technical and scientific terms used herein are to becommonly understood as by one of ordinary skill in the art to which theinvention belongs, unless otherwise defined.

The present invention may be implemented in the testing or practice withmethods and materials equivalent or similar to those described herein.

While the invention has been described with respect to a limited numberof embodiments, these should not be construed as limitations on thescope of the invention, but rather as exemplifications of some of thepreferred embodiments. Other possible variations, modifications, andapplications are also within the scope of the invention. Accordingly,the scope of the invention should not be limited by what has thus farbeen described, but by the appended claims and their legal equivalents.

All publications, patents and patent applications mentioned in thisspecification are herein incorporated in their entirety by referenceinto the specification, to the same extent as if each individualpublication, patent or patent application was specifically andindividually indicated to be incorporated herein by reference. Inaddition, citation or identification of any reference in thisapplication shall not be construed as an admission that such referenceis available as prior art to the present invention. To the extent thatsection headings are used, they should not be construed as necessarilylimiting.

What is claimed is:
 1. A method for determining whether there is atleast one object within a target medium, the method comprising:transmitting a plurality of RF signals by a radio frequency (RF) antennaarray to the target medium, wherein said RF antenna array comprises aplurality of RF antennas; receiving a plurality of reflected RF signalsfrom the target medium; combining coherently the reflected RF signals bycompensating for the occurred propagation delays within the targetmedium; estimating the propagation delays, wherein the delays areestimated from a subset of received RF signals; and determining based onsaid estimation whether there is at least one object within the targetmedium.
 2. The method of claim 1, wherein the delay is estimated using adedicated frequency sub-band of the reflected RF signals.
 3. The methodof claim 1, comprising providing an image of the at least one objectlocation.
 4. The method of claim 3, wherein the image is a twodimensional (2D) or a three dimensional (3D) image.
 5. The method ofclaim 1 comprising providing the intensity of the reflected RF signal ofthe at least one object.
 6. The method of claim 1 wherein said RFantenna array is positioned away at a distance from the target mediumsurface.
 7. The method of claim 6, wherein the distance is constant orvariable.
 8. The method of claim 1, comprising estimating the angularorientation between the RF array and the target medium surface.
 9. Themethod of claim 6, wherein the distance between the surface of thetarget medium and the RF array is estimated using the high frequencyband of the RF reflected signals.
 10. The method of claim 1 comprisingscanning the target medium using a mobile device, wherein said mobiledevice comprising said RF antenna array.
 11. A radio frequency (RF)system for determining whether there is at least one object within atarget medium, the system comprising a generation and receptionsubsystem configured to generate and receive a plurality of RF signals;an RF antenna array, the RF antenna array comprises a plurality of RFantennas configured to transmit the plurality of RF signals towards thetarget medium and receive a plurality of RF signals reflected from thetarget medium; a data acquisition subsystem configured to receive andstore said plurality of reflected RF signals; and at least oneprocessor, said at least one processor is configured to: combinecoherently the reflected RF signals by compensating for the occurredpropagation delays within the target medium; estimate the propagationdelays, wherein the delays are estimated from a subset of received RFsignals; and determine based on said estimation whether there is atleast one object within the target medium.
 12. The system of claim 11,wherein the at least one processor is further configured to provide animage of the at least one object location.
 13. The system of claim 12,wherein the system comprises a display and wherein the image isdisplayed on said display.
 14. The system of claim 11, wherein the atleast one processor is further configured to provide the intensity ofthe plurality of reflected RF signals.
 15. The system of claim 11,wherein said at least one processor is configured to analyze the angularorientation between the antenna array and the target medium surface. 16.The system of claim 11, wherein an interim medium is located between thetarget medium and the antenna array of the imaging system and theantenna array is positioned or moved in a distance from the targetmedium.
 17. The system of claim 11, wherein the distance is constant orvariable.
 18. The system of claim 16, wherein an interim medium islocated between the target medium and the antenna array of the imagingsystem and the RF array is positioned or moved in the distance from thetarget medium.
 19. The system of claim 16, wherein the interim medium orthe target medium is selected from the group consisting of: air,concrete, plaster, fluids, human tissues.
 20. The system of claim 10,wherein the RF signals are Ultra Wide Band signals.